1. Field of the Invention
Example embodiments of the present invention relate to light emitting devices and methods for manufacturing the same. At least one example embodiment of the present invention provides a nitride-based light emitting device having increased power and/or life span and a method of manufacturing the same.
2. Description of the Conventional Art
Conventional light emitting devices, such as light emitting diodes (LED), are semiconductor PN junction diodes. PN junctions of III-V group compound semiconductor may be created by combining III-group and V-group elements from the periodic table. A III-V compound semiconductor may have a higher luminous efficiency, for example, the luminous efficiency may be close or substantially close to 100% which may be higher than silicon. Thus, LEDs may be used in, for example, diode lasers. In addition, because electrons move at higher speeds in LEDs and LEDs may operate at higher temperatures, LEDs may be used in higher-speed and/or higher-power electronic devices. For example, several III-group and V-group elements may be combined to manufacture semiconductors having a variety of material composition and/or characteristics may be manufactured.
Characteristics of LEDs may be luminosity, brightness and/or radiant flux in a visible ray region may. Luminosity may be represented by light velocity per unit cubic angle or Candelas (cd), and brightness may be indicated by luminosity per unit area. A photometer may be used to measure luminosity. Radiant flux represents power radiated from all wavelengths of an LED, and may be represented by energy radiated per unit time or Watts (W).
Luminous efficiency may be used in determining a visible ray LED performance. Luminous efficiency may be represented by Lumens per Watt (lm/W). This corresponds to wall-plug efficiency (e.g., optical output/input electric power quantity) considering the human eyes' luminosity factor. Luminous efficiency of an LED may be determined by three factors, such as internal quantum efficiency, extraction efficiency and operating voltage.
In accordance with the conventional art, LEDs may have a sapphire/n-GaN/MQW/p-GaN structure. However, in such LEDs, defect density may be higher due to manufacturing limitations. Thus, internal quantum efficiency of an MQW layer and/or manufacturing higher-power LEDs may be limited. In higher-power LEDs, due to the defects, a leakage current may be larger, which may increase a driving voltage of a device and/or reduce the life span of the device.
An example, conventional LED may have a nano rod array structure with an InGaN quantum well. In this example, a method of manufacturing the nano rod may be more complicated and/or it may be difficult to actually utilize such a technology in industry.